Synergistic insecticidal compositions



United States Patent M t r 2,970,940 SYNERGISTIC INSECTICIDAL COMPOSITIONS Howard A. Jones and John A. Garman, Baltimore, Md., and Berton C. Dickinson, Lydonville, N.Y., assignors to Food Machinery and Chemical Corporation, New York, N.Y., a corporation of Delaware No Drawing. Original application Mar. 24, 1955, Ser. No. 496,596. Divided and this application Nov. 5, 1958, Ser. No. 771,949

2 Claims. (Cl. 167-22) This invention relates broadly to insecticidal compositions, and moreparticularly to insecticidal compositions containing an organic carbamate acid derivative and 0,0-dimethyl S-(l, Z-dicarbethoxyethyl) dithiophosphate, hereinafter referred to as Malathion. More particularly, this invention relates to synergisticinsecticidal compositions of these compounds wherein the insecticidal effectiveness of each component is enhanced by the presence of the other to produce anunexpected combined effect.

When two or more substances in combination show an unexpectedly high activity, as, for instance, insecticidal activity, the resulting phenomenon is called synergism. The mechanism of synergism is by no means understood. It is, in fact, quite probable that it differs with different synergistic combinations. The term synergism can be defined, however, as a cooperative action which is encountered in combinations of two or more biologically active components in which the combined activity otthe two components exceeds the sum of the activities of the components when used alone. The insecticidal activity of the mixed components cannot be predicted from known values of the individual components, but is unpredictable and depends on the individual activity of neither.

It is an object of this invention to provide insecticidal compositions of enhancedkilling power. Another object of this invention is to produce novel compositions containing compounds, capable of synergizing the knockdown and killing properties of individual toxicants. A further object of this invention is to provide compositions including a relatively toxic phosphorus containing insecticide in which superior insecticidal activity is obtained because of the synergistic effects, but in which the ultimate toxicity to warm-blooded animals is greatly reduced because of the lower concentrations of the phosphorous compounds required when used in combination with the relatively less toxic carbamates. Other objects and advantages of the invention will become apparent from the description of the invention set forth below.

According to this invention, there are provided synergistic insecticidal compositions comprising 0,0-dirnethyl S-(l, Z-dicarbethoxyethyl) dithiophosphate, hereinafter called Malathion and phenyl N-methyl-N-phenylcarbamate. This carbamate may be prepared as described in copending application Ser. No. 812,113, filed May 11, 1959.

The synergistic insecticidal compositions of this invention may be used on a wide variety of insect and mite species, but are particularly effective against such insects as the two-spotted spider mite of the squash bug. The combinations are highly effective and economical to use for such large-scale insecticidal requirements as the control of truck crop, forage crop and orchard insects.

The synergistic compositions of this invention can be formulated as aqueous emulsions, as dry or wettable powders, as solutions or in any other suitable vehicle. The insecticidal compositions can be utilized as sprays, as dusts, as aerosol mixtures, insecticidal coating compositions, and as residues. In general, they can be applied by methods commonly used for control or eradication of insects, mites and the like. Thus these insecticidal compositions can be formulated with solvents,

2,970,940 Patented Feb. 7, 1961 diluents and carrier media, adhesives, spreading, wetting and emulsifying agents and other ingredients.

The relative propositions of the active ingredients as well as inert carriers, solvents, dispersants and the like may vary within wide limits.

Thus the relative proportion (ratio) of the Malathion to the carbamate ester can range from 20 parts of the former per 1 part of the latter to 1 part of the former per 40 parts of the latter and preferably about 1 part of the former to about 2 parts of the latter.

The quantities of the component toxicants in the final insecticidal compositions can range from 0.01% to 25.00% for the Malathion and from 0. 05% to 50.00% for the carbamate, and preferably from 0.10% to 10.00% for the Malathion and from 0.10% to 25.00% for the carbamate.

The procedures of the testing methods are described below. The details of the test experiments including the type of formulation and mode of application or dosing, and the species of insects which served as test subjects are given in the examples.

Insects used in the testing included the house fiy (Musca domestica L.), Mexican bean beetle (Epilachna varivestis Muls.), pea aphid (Macrosipum pisi. [Kitb.]), two-spotted spider mite (Tetranychus bimaculatus Harvey), harlequin bug (Murgantia histrionica [Hahn]), and squash bug (Armsa tristis).

The test methods used are described as follows:

Dust tower method This general method is described in the following reference, Moore J. Econ. Ent. 43, No. 2, 188-190 (1950).

The dusting apparatus consists of a vertical glass cylinder, 34 inches high and 8.5 inches in diameter, into which the appropriate dust sample is discharged through a small hole in the center of the cover, by means of a small laboratory duster operating at an air pressure of 40 p.s.i.g. The duster assembly comprises at 10 ml. beaker, into which the weighed sample is placed, and fitted with a rubber stopper through which pass the air inlet and dust outlet tubes, both of which are made of 4 inch diameter copper tubing. At the outer end of the air inlet tube is a trigger valve that serves as a control for dispensing the dust. The inner end of this tube reaches nearly to the bottom of the beaker. The end of it is sealed but, along the sides, seven 0.032 inch holes are drilled at irregular intervals whichserve as air inlets. Such an arrangement causes pronounced turbulence of the dust and thus insures exhausting the complete sample from the beaker. The dust outlet tube forms an arch from the top of the beaker to the top of the glass dusting tower.

After discharge of the sample into the tower, there is allowed a 2-minute settling time before removal of foliage or insects being treated. A weighed metal plate is placed in the tower each time a test is made, and by weighing the amount of dust deposited on it, it is then possible to calculate the amount applied pet-acre.

Because of day-to-day variations in the results obtained by this test method, comparisons among the individual components and their combinations were made simultaneously in order to minimize this source of variation.

Slight modifications in this test employed for specific insect species are as noted below.

Squash bug.For this test squash leaves were collected in the field and the cut ends of the stem were wrapped in moist cotton. Individual leaves were then placed in 3.5 inch Petri dishes and dusted as described above. Each treated leaf was then infested withlO last instar squash bug nymphs and the covers of the Petri dishes were replaced. At the end of 24 hours the treated leaves were removed and fresh untreated leaves were introduced into the dishes. Mortality counts were taken after the bugs had been on the untreated leaves for 24 hours.

Two-spotted spider mite.In tests on two-spotted spider mites, the mites were confined to the upper surfaces of potted bean plants by a Tanglefoot ring. The bean plants were placed in the glass tower and the mites direct-dusted. Mortality readings were taken in 24 hours. Only adult mites were used in determining mortality counts.

nents being employed in the ratio of about 2 parts of said carbamatees t er to about 1 part of said dithiophosphate.

2. A method of killing insects which comprises applying to the insects and their habitat synergistic insecticidal compositions comprising 0,0-dirnethyl S-(l, 2-dicarbethoxyethyl) dithiophosphate and phenyl N-methyl-N- phenylcarbamate, said components being employed in the ratio of about 2 parts of said carbamate ester to about 1 part of said dithiophosphate.

TABLE 1 NCOR Dust Dust Ratio Mortality R R R Conc. Name Conc. (lbs/A.) Test Method Test Subject (percent) (percent) (percent) Methy1 Pheny1. PhenyL. 0.5 11.3 Dust Tower Ttfiiipotted Spider 1 e. Malathlom- 0.25 10.7 .....do. do 9 Do Phenyl. PhenyL. 0.5 do 0.25 11.2 do do.. 100 Do do. do. 0.5 53.3 -do Squash B 0 Malathion 0.25 46.6 .do. 10 Do Phenyl PhenyL. 0.5 .do 0.25 46.6 do ..do 60 The data in this table demonstrate the unexpected efiectiveness of the compositions of this invention against such insects as the Mexican bean beetle and the squash bug.

This application is a division of copending application Serial No. 496,596 filed March 24, 1955, now abandoned, which is a continuation-in-part of Serial No. 427,374, filed May 3, 1954, now abandoned.

We claim:

1. Synergistic insecticidal compositions comprising 0,0-dimethyl S-(l, 2-dicarbethoxyethyl) dithiophosphate References Cited in the file of this patent UNITED STATES PATENTS Jelinek Apr. 11, 1950 Gysin May 25, 1954 OTHER REFERENCES King: US. Dept. Agr. Handbook No. 69, May 1954, pp. 105-108.

Chemical Age., vol. 53, No. 1631 (1950), p. 540. 1 gharpz Agr. News Letter, January-February 1952, pp. Roark: US. Dept. Agr. Bulletin E-344 (May 1935), pp. 2-6.

Frear: Chem. of the Pesticides, 3rd ed., January 1955,

and phenyl N-methyl-N-phenylcarbamate, said compopp. 73-91. 

2. A METHOD OF KILLING INSECTS WHICH COMPRISES APPLYING TO THE INSECTS AND THEIR HABITAT SYNERGISTIC INSECTICIDAL COMPOSITIONS COMPRISING 0,0-DIMETHYL S-(1, 2-DICARBETHOXYETHYL) DITHIOPHOSPHATE AND PHENYL N-METHYL-NPHENYCARBAMATE, SAID COMPONENTS BEING EMPLOYED IN THE RATIO OF ABOUT 2 PARTS OF SAID CARBAMATE ESTER TO ABOUT 1 PART OF SAID DITHIOPHOSPHATE. 